The Clearomizer Plus (CE4+) cartridge vaporizes thin oils and liquids when used with your standard 510 (eGo style) battery. To fill this clearomizer just unscrew the black mouthpiece and drip up to 1.6mL of your favorite e-juice in. The clear wall allows you to see exactly how much e-liquid you have left, taking all of the guess work out of refilling. This cartridge also features an atomizer that can easily be replaced when the flavor begins to diminish rather than replacing the entire clearomizer.